This invention relates to gas burners and particularly relates to a burner system for natural gas or propane fireplaces, fireplace inserts and assemblies of gas burners with non-combustible fire logs provided thereon and commonly referred to as gas logs for use in a fire box of a gas fireplace.
Gas appliances for fireplaces are becoming more popular due to their convenience, cleanliness an economy in use. The flame patterns produced by gas appliances are, however, not comparable to those produced by burning natural wood logs in the fireplace. When wood logs are burned in a fireplace, the flames flicker in an attractive desirable asymmetrical fashion, originating randomly from the log arrangement and without reliance on linkage between other flames in the log arrangement. Flames can be seen to follow the contours of the logs as the flames rise above the logs. Glowing embers are interspersed around and under the burning logs throughout the burn area. Whereas in a gas fireplace, gas insert or gas logs, the flames appear in an orderly fashion in one or two parallel rows. If glowing embers are present, they usually appear in a linear arrangement along the base of the front row of flames.
Unlike wood fires, products which produce flames using natural gas or propane must meet strict safety requirements with respect to the amount of carbon monoxide that these appliances can produce as well as numerous operating characteristics which ensure a high level of safety. These requirements make it more difficult to produce a gas fire that is as appealing as a wood fire. For example, the generation of desirable tall yellow flames in a gas fireplace consistent with the appearance of flames of a wood fire in itself causes the inherent production of carbon monoxide. Moreover, additional and unacceptable levels of carbon monoxide can be generated when such yellow flames come in contact with the relatively cool surfaces of the non-combustible artificial logs commonly used in the gas fireplaces. Therefore, it becomes important to have a good measure of control over the gas flames so that the flames can be produced close to the non-combustible logs for added realism and also to minimize the flame impingement that can lead to the unacceptable levels of carbon monoxide as well as excessive carbon deposit.
With gas fireplaces, gas inserts and gas logs, it is common to have front and rear logs placed parallel to the face of the fireplace with continuous flames running in parallel lines in front and between these logs. These lower logs support one or more upper logs arranged in a transverse fashion over the lower logs. Such an arrangement of logs, results in the blockage of view to flames and embers as would be found in a wood fire. Furthermore, such an arrangement of logs produces flames appearing in an orderly fashion with an obvious connection to the other flames in the fire, and it is greatly lacking in realism to the usually random placement of logs and resulting flames in a natural wood fireplace.